1. Field of the Invention
The present invention relates to a gas circuit breaker in which an electric circuit for a higher current is opened by the use of gas, and, more particularly, to a puffer type gas circuit breaker.
2. Description of the Related Art
In a puffer type gas circuit breaker, for example, as disclosed in U.S. Pat. No. 3,839,613 when a movable contactor is opened and travels from a fixed contactor, pressurized gas in a puffer cylinder operatively connected with the traveling of this movable contactor is blown against an arc formed between the movable contactor and the fixed contactor, with the gas flow being in the direction of traveling of the movable contactor and the reverse direction thereof. For this reason, the arc between the movable contactor and the fixed contactor is extinguished so as to break the current between these contactors.
In such a type of known gas circuit breaker, the pressurization of the gas in order to generate the arc-extinguishing gas is significant and, for this reason, the diameter of the puffer cylinder is large. Accordingly, a problem arises in that it is necessary to increase the driving force for driving the puffer cylinder. The gas which has extinguished the arc is heated by the arc and exhausted to the outside of the circuit breaker portion through an exhaust passage, with the gas flow having a high temperature thereby causing a problem of damaging the internal surface of the exhaust passage.